The effect of nutritional regimes upon collagen concentration and survival of rats

It has been demonstrated that food restriction put upon animals at any stage of the individual's life, if chronic, produces a distinct increase in the lifespan. This can be effected in youth and still have a distinct effect in old age even if the food restriction is cut down and for the rest of the life the animal is allowed food ad libitum. Since the effect upon the aging of the animal is delayed on the time scale, it is obviously an effect which is stored somewhere and it is suggested that this storage occurred somewhere along the DNA-RNA pathway. Also the effect of under nutrition is not identical with that of oxidizing free radical blocking agents and therefore it is concluded that the food deprivation does not minimize the attack of the free radicals on the long chain macromolecules and as a matter of fact it seems that the proportion by which free radicals contribute to the changes in the average lifespan in undernourished and fully nourished animals is small. It has been also demonstrated that the addition of reducing agents to normal diet and to the diet of food restricted animals increases the average and maximum lifespan in both cases practically to the same extent, which supports the idea expressed before. This feeding effect has been observed in three different species of rodents and no extrapolation has been done to other types of mammals. Due to the data published on this topic and dealing with rotifers and some insects (2) it is conceivable to conclude that the effect of undernutrition is general and is not limited to the food restriction in the early stages of development only. Collagen starts to accumulate in the kidneys and liver of experimental animals roughly ten months before 90 percent of the population dies out. Tus an increase in collagen concentration can be indicative of involutional changes in the organ (and perhaps organism). These data are i- good agreement with previously published results on the relation between collagen accumulation and chronic food deprivation in rats (6). It can be also concluded that food deprivation induced in the adult, though not so effective in life prolongation as the food restriction during early development, still can increase survival in experimental animals to a high degree.